The event brought together the world number one and his teammates - Keegan Bradley, Sam Burns, and Luke Clanton - against Masters champion McIlroy and his team of Luke Donald, Shane Lowry, and Haotong Li in a series of inventive contests, including a relay race and a timed driving challenge.
The Americans surged ahead early, taking the opening points in the driving and short-game competitions, but McIlroy's squad responded with a win in the team relay to stay in contention.
In the fourth contest, Clanton excelled in the 14-club challenge, giving the Americans a 3-1 advantage. However, a bonus-point victory in the final closest-to-the-pin challenge evened the score, forcing a dramatic play-off between the two stars.
In the decider, Scheffler sank his 47-yard shot just an inch closer to the hole than McIlroy, securing a narrow triumph for the American team.
Scheffler capped off an exceptional season, becoming only the second player after Tiger Woods to win PGA Tour Player of the Year at least four consecutive times. He led the Tour with six victories, including major titles at the PGA Championship and The Open.
Additionally, he became the first player since Woods in 2000 to post the lowest scoring average across all four rounds on the PGA Tour.
Scottie Scheffler drew further comparisons with Tiger Woods on Monday after becoming just the second player to claim PGA Tour Player of the Year honours four times consecutively.
Rasmus Neergaard-Petersen will carry a two-shot advantage into the final round of the Crown Australian Open after a strong finish in Melbourne on Saturday.
Rory McIlroy was staring at a missed cut until a late burst of three birdies over his last four holes booked his place in the weekend at the Crown Australian Open.
Elvis Smylie, Ryan Fox and Carlos Ortiz shared a two-shot lead after mastering tricky, windy conditions on day one of the Crown Australian Open at Royal Melbourne.
